This invention relates to flexible ceramic fiber boards containing a latex binder.
Ceramic fibers are widely used in the fabrication of blankets, felts and boards for high temperature insulation. These are used primarily for lining furnaces. Such products may contain non-crystalline aluminosilicate fibers, crystalline high alumina fibers or a mixture of the two types of fibers. Non-crystalline or amorphous fibers are ceramic fibers formed from a melt. The molten composition is fiberized by spinning or blowing and then quenching rapidly to retain a non-crystalline structure. Crystalline ceramic fibers are generally produced by heat treating a precursor fiber containing chemical compounds which convert to high temperature oxides upon heat treating. The precursor fibers are made by textile processing techniques such as dry spinning of solutions or by spinning of a viscose solution through orifices of a rotating disc. The heat treating process is usually a complex process involving decomposition, oxidation, rearrangement of molecular structure and sintering. This long heat treating process results in a crystalline form of ceramic fiber. The non-crystalline aluminosilicate fibers generally have high mechanical strength and comparatively high shrinkage while the crystalline high alumina fibers have lower mechanical strength and lower shrinkage. Mixtures of the fibers are used to obtain the benefits of each type.
Boards formed from ceramic fibers with a latex binder have also been used in the past. These boards are formed by a wet process whereby the fibers and binder are dispersed in water to form a slurry. The slurry is brought into contact with a porous mold and a vacuum is drawn on the other side of the mold to attract the fibers to the mold surface. This forms a shape of the fibers and binder on the mold. The shape is then removed from the mold and dried to form the board.